Fault Ride-Through Capability of Cascaded Current-Source Converter-Based Offshore Wind Farm

Abstract

This paper presents a novel fault ride-through (FRT) strategy for the permanent-magnet synchronous generator (PMSG)-based offshore wind farm, where cascaded current- source converters (CSCs) are employed on both the generator- and grid-side. The inherent short-circuit operating capability of the CSC is used to develop the FRT strategy, and at the same time, the grid-side converters fulfill the demanding reactive power requirement imposed by recent grid codes. Intensive simulation results are provided to ensure the validity and feasibility of the proposed FRT method. Moreover, the inherent short-circuit operating capability of the CSC contributes to a great operating flexibility for the proposed wind farm. Specifically, the faulty turbine-generator unit can be easily isolated from the cascaded system without affecting the operation of other series interconnected wind turbines. Both simulation and experimental verifications are provided for the operating flexibility of the cascaded CSC-based wind farm by isolating one wind generator from the system.